Grenade projectile

ABSTRACT

A projectile for grenade launchers and mortars in which the projectile includes a body portion and a tail or stabilizing portion. The maximum diameter of the projectile is at the band portion of the body and is represented by D. Improved range and accuracy are obtained by shaping the body to conform with a Karmann profile, locating the band so it is 2.2D-2.6D from the nose of the body, using a projectile of an overall length L in a range of from 5.2-5.5D, and terminating the inwardly tapering Karmann profile at the rear of the body at an ogival form with a diameter of approximately 0.35D which merges with a straight trailing portion. The usual sleeve and stabilizing fin arrangement is provided at the rear of the projectile.

limited States Patent 1 Donner et al.

[ 51 May 8,1973

[ GRENADE PROJECTILE FoRElo PATENTS 0 APELIQATIONS 657,384 11/1963 Italy ..102/49.l

Primary ExaminerVerlin R. Pendegrass AttorneyLowry, Rinehart, Markva & Smith '57 ABSTRACT A projectile for grenade launchers and mortars in which the projectile includes a body portion and a tail or stabilizing portion. The maximum diameter of the projectile is at the band portion of the body and is represented by D. Improved range and accuracy are obtained by shaping the body to conform with a Karmann profile, locating the band so it is 2.2D-2.6D from the nose of the body, using a projectile of an overall length L in a range of from 5.2-5.5D, and ter minating the inwardly tapering Karmann profile at the rear of the body at an ogival form with a diameter of approximately 0.35D which merges with a straight trailing portion. The usual sleeve and stabilizing fin arrangement is provided at the rear of the projectile.

5 Claims, 1 Drawing Figure pere, both of Finland [73] Assigneez Etablissement Salgad, Vaduz,

Liechtenstein [22] Filed: Dec. 21, 1970 [2]] Appl. No.:- 99,772

52 us. cl; ..102/49.2

[5l] Int. Cl ..F42b 13/22 [58] Field of Search ..102/49.l, 49.2

[56] References Cited UNITED STATES PATENTS 2,1 13,313 4/1938 Brandt ..l02/49.2

7 3 ,2 l 2 D l GRENADE PROJECTILE This invention relates to a grenade or mortar projectile of the type having a band surrounding the projectile at its largest diameter. The band is of the type which engages the barrel of a grenade launcher. The band also co-operates with a finned end portion of the projectile to stabilize the projectile during flight.

Various types of fin stabilized grenade projectiles are known in the prior art. The form and dimensions of the grenade body and the end or finned portion contribute significantly to the characteristics of the projectile in flight. The range of travel of the projectile and its accuracy are dependent on a number of factors, each of which have little effect alone but which cumulatively significantly influence the flight performance of the grenades in either a favorable or unfavorable manner. The diameter of the grenade is determined by its caliber, and the weight of the projectile is a function of the caliber. This is true even though the grenades have a different external shape so the weight of grenades of the same caliber differ.

Correspondingly, for a particular construction of a grenade projectile, one obtains a certain predetermined relationship between the location of the center of gravity and the angle or point of attack of the air resistance or drag acting on the projectile during flight, and this relationship depends on several factors including the overall length of the projectile.

In previously known grenade projectiles, ranges or distances obtained for a certain caliber of grenade are generally on the same order of magnitude, even though the form of the projectiles deviates widely, one to the other. Hence, the combinations of factors previously selected which contribute to the flight performance of the grenade, have resulted in no significant noticeable improvements which contribute'to increasing the range of the grenade. With the known existing constructions and profiles of grenades, the difference in the average range of grenades of like caliber does not exceed 6 percent.

The object of the present invention is to provide a grenade or mortar projectile of considerably improved flight characteristics such that both the range and accuracy of the projectile is substantially better than prior grenade projectiles.

This object is achieved in accordance with this invention by so shaping the projectile between the nose and the mid-line of the band that the surface of the projectile has a shape corresponding to the so-called Karmann profile. In addition, it has been found that improved range and accuracy further results from shaping the portion of the projectile from the mid-line of the band to likewise correspond to a Karmann profile which tapers rearwardly, and wherein the ratio L/D between the overall length of the projectile and the largest diameter at the band is in the range of L/D 5.2-5.5.

it has been found that such a combination of the various dimensions in the environment of a grenade or mortar projectile provides the unexpected results that the projectile maintains a stable flight path and has a range which exceeds by about 15 percent, the range of previously known grenades of the same caliber. In grenades having a caliber of 140 millimeters the range of the grenade of this invention is 15 percent greater than previously known grenades. In addition, excellent accuracy is obtained in that a grenade of this type which has a range of about 8 kilometers has excellent accuracy, since at the 8 kilometer range, grouping of the projectiles is in a strike zone with a radius of 28 meters.

Numerous other objects, features, and advantages of this invention will become apparent with reference to the drawing which schematically shows a grenade projectile in plan with portions thereof cut away for purposes of explanation.

As shown in the drawings, the projectile 1 is elongated, and has a nose portion 2, a band 3, and a tail structure 4. Tail structure 4 includes a generally cylindrical sleeve 5 with stabilizing tail fins 6 within the sleeve which stabilize the flight of the projectile. As shown in the drawing, the maximum diameter of the projectile at band 3 equals D, and the length of the projectile from the tip of nose portion 2 to the rear of tail portion 4 is equal to the length L. Also shown on the drawing is the radius r, the distance from the center line of the axis of the projectile to the outside surface 7 of the portion of the projectile between the nose 2 and the maximum diameter at the band 3. The distance x shown at the drawing is the distance along the axis of the projectile, from the tip of the nose 2 to the location where the radius r is measured.

The improved flight and range characteristics of the projectile of this invention are attributed in part to the profile of the surface 7 of the projectile as well as to the profile of the surface 8 of the projectile. The surface 8 is that portion of the projectile which tapers or curves inwardly in a direction toward the tail structure 4. The profile of the surface 7 is substantially a Karmann profile, as determined by the following formula:

where:

r= radius of projectile at distance x from nose 0 gravitational constant A;

in addition, the profile of surface 8 also takes the form of a Karmann profile but which tapers inwardly. It will be observed with reference to the drawing that the length of the projectile from nose 2 to the maximum diameter at the band 3 lies in the range of 2.2-2.6D. The length of the surface 8 is also related to the diameter in that the distance from the maximum diameter at the band 3 to the point at which the Karmann profile terminates is 2 D. it will also be observed that the diameter of the projectile at the point of termination of the rearwardly tapering Karmann profile at the line 9 is from 0.38-0.45D. At the line 9, the body of the projectile has an ogival curvature such that a diameter 10 in front of the rear portion 4 of the projectile has a diameter of 0.35D whereas the portion 11 at the rear of the projectile has a constant diameter less than D/2.8. Since the ratio D/2.8 equals 0.357, it is apparent that the diameter of the tube portion H can be very slightly along the line 12 such that the projectile has a flat circular impact surface of a diameter less than 0.15 D.

A projectile constructed in accordance with the described profile and dimensional relationship was found to have an increased range of approximately 15 percent over existing grenade or mortar projectiles and also exhibits improved accuracy even at long ranges.

While a preferred embodiment of the grenade launcher or mortar projectile of this invention has been shown, and described herein in detail, it is to be understood that changes can be made without departing from the scope of this invention as stated herein and defined in the appended claims.

What is claimed is:

l. A grenade projectile comprising a body having a nose and a band spaced from the nose and surrounding the largest diameter thereof;

a tail portion connected to said body and having fins cooperating with said band to stabilize and direct the projectile;

said body from the point of said nose to said band having a Karmann profile, said Karmann profile being determined by the following formula:

r radius of projectile at distance x from nose gravitational constant a substantial portion of said body from said band to said tail having a Karmann profile which tapers inwardly; and

said projectile having an overall length, L, in the range of 5.2D 5.5D, where D is the maximum diameter of the band.

2. A projectile according to claim 1 wherein the diameter of the projectile at a distance 2D from the band toward the tail is in the range of 0.38D-0 .45D.

3. A projectile according to claim 1 wherein said nose is flat and in the shape of a circle of a diameter less than 0.15D.

4. A projectile according to claim 1 wherein the distance from the nose to the band is in the range of 2.2D-2.6D.

5. A projectile according to claim 1 wherein said inwardly tapered Karmann profile terminates at a location approximately 2D from the band toward the tail;

the profile at the point of termination has an ogival form to provide a diameter of 0.35D at a location in front of the fins; and

a portion of a constant diameter less than D/2.8 extends from the ogival form. 

1. A grenade projectile comprising a body having a nose and a band spaced from the nose and surrounding the largest diameter thereof; a tail portion connected to said body and having fins cooperating with said band to stabilize and direct the projectile; said body from the point of said nose to said band having a Karmann profile, said Karmann profile being determined by the following formula: r (1/ square root pi ) square root phi - 1/2 Sin 2 phi C Sin 3 phi where: phi Cos 1 (1 - 2x) r radius of projectile at distance x from nose c gravitational constant a substantial portion of said body from said band to said tail having a Karmann profile which tapers inwardly; and said projectile having an overall length, L, in the range of 5.2D - 5.5D, where D is the maximum diameter of the band.
 2. A projectile according to claim 1 wherein the diameter of the projectile at a distance 2D from the band toward the tail is in the range of 0.38D-0.45D.
 3. A projectile according to claim 1 wherein said nose is flat and in the shape of a circle of a diameter less than 0.15D.
 4. A projectile according to claim 1 wherein the distance from the nose to the band is in the range of 2.2D-2.6D.
 5. A projectile according to claim 1 wherein said inwardly tapered Karmann profile terminates at a location approximately 2D from the band toward the tail; the profile at the point of termination has an ogival form to provide a diameter of 0.35D at a location in front of the fins; and a portion of a constant diameter less than D/2.8 extends from the ogival form. 